866861617 has 2 divisors, whose sum is σ = 866861618. Its totient is φ = 866861616.

The previous prime is 866861563. The next prime is 866861621. The reversal of 866861617 is 716168668.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 776402496 + 90459121 = 27864^2 + 9511^2 .

It is a cyclic number.

It is not a de Polignac number, because 866861617 - 2²³ = 858473009 is a prime.

It is not a weakly prime, because it can be changed into another prime (866861627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433430808 + 433430809.

It is an arithmetic number, because the mean of its divisors is an integer number (433430809).

Almost surely, 2^866861617 is an apocalyptic number.

It is an amenable number.

866861617 is a deficient number, since it is larger than the sum of its proper divisors (1).

866861617 is an equidigital number, since it uses as much as digits as its factorization.

866861617 is an evil number, because the sum of its binary digits is even.

The product of its digits is 580608, while the sum is 49.

The square root of 866861617 is about 29442.5137683588. The cubic root of 866861617 is about 953.4909848847.

The spelling of 866861617 in words is "eight hundred sixty-six million, eight hundred sixty-one thousand, six hundred seventeen".